#define _CRT_SECURE_NO_WARNINGS	

#include<stdio.h>

int main()
{
    int x, y;
    scanf("%d%d", &x, &y);
    double s1 = x * y * 1.0 / 2;
    double s2 = (100 - x) * (100 - y) * 1.0 / 2;
    double s3 = (100 - x) * y;
    printf("%.2f", 50 * 100 - s1 - s2 - s3);
    return 0;
}